My first "sensei" encouraged learning the weapons early and often. Of course he wouldn't teach you anything unless you paid for those classes which were convienlenty separate.
That was a long time ago. My opinion regarding weapons training is: Train early, often, and continuously with both the bokken and jo. They will in-effect teach you many aspects of aikido. If also you practice jo dori and bokken dori, you've pretty much got a complete package (except ukemi
) . Not bad for two wooden sticks.